Conventionally, a vehicle seat reclining device disclosed in the patent document 1 is known. As shown in FIGS. 1, 3 through 6 of the patent document 1, the vehicle seat reclining device includes a first arm (lower arm 1) fixed to one of a seat cushion side and a seat back, a second arm (upper arm 2) relatively rotatably supported by the first arm and supported by the other of the seat cushion and the seat back, a plurality of pawls (pawl 50, 60) provided at the first arm and a portion to be engaged (internal toothed portion 25a) provided at the second arm and engaged with the plurality of pawls. According to this vehicle seat reclining device, the plurality of pawls include a first pawl 50 (one is provided) and a second pawl 60 (two pawls are provided) and a contacting portion (projection 51) is provided only at the first pawl 50 and a portion to be contacted (projection 27) is provided at the second arm for preventing the engagement action between the pawl and the portion to be engaged by the engagement between the contacting portion (51) and the portion to be contacted.
According to thus structured vehicle seat reclining device, when the operating handle 85 is released after rotating the seat back within a so-called frontward tilting angle relative to the seat cushion under the lock being released, the cam 40 pushes the pawl 50 in a direction of engagement with the internal toothed portion 25a by the biasing force of spring 86. However, the movement of the pawl 50 is restricted and no engagement with the internal toothed portion. The other two pawls are positioned where the engagement with the internal toothed portion cannot be attained by the function of an elongated cam hole 66 and a projection pin 47. Thus, the seat back can be rotated without being locked within the frontward tilting angle range.
Patent Document 1: JA 2003-9978 A